A/C blowing only hot air

[marlboro]

Please help me troubleshoot my aircon problems. Since couple of days ago the aircon started blowing only hot air. It is not stuck in ECON mode. I took it to a place to refill the gas but they couldn't refill it and told me, there is gas inside but the problem is somewhere else. Then they connected a multimeter to the connector going to the compressor and told me the voltage is 0. Not sure why there is no voltage supplied to the compressor or if they tested it properly because they tried to pierce the wire insulation, instead of disconnecting the connector. I scanned the car with VCDS full version and there is no errors on the Auto HVAC module. I also ran log on some of the values with the aircon switched on and the following came up:

0.000 A A/C Valve (N280) Current
0.0 % A/C Valve (N280) Duty Cycle
29.5 % High-Pressure Signal (G65)
8.0 bar Refrigerant Circuit Pressure
5.0 Current Shut-Off Criteria
1.0 Last Shut-Off Criteria
12.0 Second to Last Shut-Off Criteria
1.0 Third to Last Shut-Off Criteria
20.0 Current Value
25.0 Specified Value
28.0 Minimum Position (Cooling)
223.0 Maximum Position (Heating)

Tried checking fuses 1 and 6 on the board as they both relate to the aircon but both seems to be good.

Please give me some pointers on what should I check next?

[pkny]

i had a similar problem last summer here in the states, but my high pressure was reading very high. Not sure if 8 bar is normal in this system, thats about 115 psi i believe.
So I learned that the system defaults into econ mode to prevent damage to the compressor if the pressure within the system is outside of spec.
There is a part that sits below the driver side radiator (left side) that reads the pressure. I forgot what that part is, when i get home i'll find a part number from the bentley and post it here.

[marlboro]

i had a similar problem last summer here in the states, but my high pressure was reading very high. Not sure if 8 bar is normal in this system, thats about 115 psi i believe.
So I learned that the system defaults into econ mode to prevent damage to the compressor if the pressure within the system is outside of spec.
There is a part that sits below the driver side radiator (left side) that reads the pressure. I forgot what that part is, when i get home i'll find a part number from the bentley and post it here.

Please check and let me know of the part no. Might be similar issue like yours. Initially when they tried refilling, they mentioned something about very high pressure but then I think they might have tried to empty the current gas and dropped it to 8bar.

[pkny]

For some reason i couldn't find this repair in my history.
It was this part that i replaced.
http://www.ecstuning.com/Audi-B7_A4-....0T/ES2085410/

Its pretty easy to get once you remove the front bumper and diverside headlights.

[marlboro]

For some reason i couldn't find this repair in my history.
It was this part that i replaced.
http://www.ecstuning.com/Audi-B7_A4-....0T/ES2085410/

Its pretty easy to get once you remove the front bumper and diverside headlights.

This part should be the G65 sensor. But from my logs , seems like there is signal coming from it:

29.5 % High-Pressure Signal (G65)

Not sure if 29.5% is normal.

Anyone knows how to test this sensor? May be a value for it's resistance?

[marlboro]

I went to another place to troubleshoot the aircon issues and they removed the gas and pulled the orifice tube. There are couple of small shiny bits on the metal net. According to them, these are shavings from the compressor and now everything needs to be replaced:

Compressor
Condenser
Drier
Orifice tube

The prices of all of the above are extremely high from the dealer.

And I didn't have any codes for the A/C in VCDS.

Is this the only possible solution? Do I really need to replace all of the above? What about may be repairing the compressor, etc.?

[fly300kts]

Yes and on top of that, you need to flush the entire system: lines, evaporator, etc.

Phil

[marlboro]

Thanks Phil. What about repairing the current compressor and may be reusing the current condenser? Is that an option worthwhile pursuing?

I will post some pics later of the orifice tube.

[fly300kts]

Not really and I will not use the actual condenser. It's not an expensive part (aftermarket) and if you use it, you are taking the risk of damaging again the new compressor if any metal shavings remain

Phil